This invention relates to pipe couplings, and more particularly to pipe couplings that are useable with unthreaded pipes.
Plastic pipes have become widely used in sprinkler systems because of their low cost and ease of connection and repair. Such pipes, commonly referred to as PVC because of their typical polyvinyl chloride composition, may be joined without threading by applying an adhesive such as a solvent cement type to the ends of the pipes and slipping a smooth-bore coupling over the ends.
When a break occurs in an underground sprinkler system of the PVC type, it can be repaired by digging away the dirt over the break, cutting out a small section of pipe containing the break, and connecting a new section of pipe in place using a pair of couplings. In practice, however, great difficulty is encountered in installing the couplings. The couplings can be installed by bending the pipe in the ground far enough so that the gap between them is increased sufficiently to insert the pipes into the couplings, and then releasing the bent pipes so they return to their original straight configuration. However, the dirt around a long section of the pipes may have to be removed to permit sufficient bending, which involves considerable labor and which may not be possible in certain locations. Also, the glue on the pipe may be scraped away while the pipe is fitted into the coupling. A coupling which could be installed without requiring large amounts of pipe bending would facilitate repairs in such sprinkler systems.